The invention relates to a water resistant slide fastener and to a process for preparing same.
Numerous water resistant articles such as high-performing outerwear, jackets, coats, pants, gloves, back packs, daypacks, tents and the like are used in a wide variety of environments and applications. These articles are typically made of water proof or water-resistant material as desired, but also typically require closures or slide fasteners such as zippers and the like which can be a source of leakage.
A number of proposals have been made to address this problem. Examples of such efforts include U.S. Pat. Nos. 4,888,859, 5,386,616 and 5,444,898.
U.S. Pat. No. 4,888,859 to Morita involves the positioning of a filling core in spaces or gaps defined by the gripping elements of a slide fastener. The core is said to swell when contacted by water so as to prevent entry of liquid into the garment. This type of slide fastener has also been used with a hydrophobic core. The back surface of the '859 slide fastener is solution coated with a layer of polyurethane resin.
A problem with the '859 fastener is that the fastener must be positioned with the polyurethane coating on the inside surface so as to protect the coating from abrasion and the like. Unfortunately this exposes the fastener structure or coils to outside wear and abrasion, can detract from the appearance of the slide fastener in the garment, and does not give the appearance of a water resistant closure to consumers.
Further, with the coating positioned inside a garment or article, it is undesirable to tape to the coating material as the material has insufficient adhesion to the underlying stringer tapes, and this adhesion drops after laundering.
Positioning of this fastener with the coating facing outward, however, also leads to problems as the coating does not stand up to abrasion, which leads to loss of performance and leakage.
U.S. Pat. No. 5,386,616 to Norvell describes a water resistant closure wherein a water resistant coating is applied to the stringer tapes of a slide fastener, and water repellant treatment is relied upon for the actual gripper structure. Unfortunately, such treatments have been found to break down when subjected to wear, tear and soiling. Therefore, the slide fastener of Norvell '616 is not suitable as the primary water resistant, and additional flaps or other structures of the garments are required. Furthermore, consumers are uncomfortable with water protection that cannot be seen, and there is therefore a low perceived value to invisible barriers such as fluorocarbon treatment and the like.
An alternative approach is disclosed in U.S. Pat. No. 5,444,898 which discloses a slide fastener wherein an internal flap is arranged to pass behind the actual grippers of the slide fastener so as to resist water seepage therethrough, and an additional flap is positioned to pass in front of the coils of the fastener structure. Although this structure serves to enhance the water resistance of the fastener, the extra flaps make for a structure which can be cumbersome and bulky, and is therefore undesirable for use with articles where flexibility is critical such as for example, "pit-zips" of high performing outerwear.
The need remains for a simple and durable slide fastener which is resistant to passage of water while maintaining a pleasing appearance without the need for additional flaps or other structure and further while resisting breakdown due to outside abrasion.
It is therefore the primary object of the present invention to provide a water resistant slide fastener which provides excellent resistance to passage of water.
It is a further object of the present invention to provide such a water resistant slide fastener which is resistant to damage due to abrasion and the like.
It is still another object of the present invention to provide a water resistant slide fastener having a water resistant layer which has excellent resistance to abrasion and loss of adhesion.
It is still another object of the present invention to provide a water resistant slide fastener which can be easily incorporated into water resistant articles or garments through a variety of methods including direct heat-sealing without securing.
Other objects and advantages of the present invention will appear hereinbelow.